Using the data of the three earthquakes (M_L>5.0) which occurred in Xunwu,Jiangxi Province in August 1987,we have discussed a travel characteristics of the π_gwave in Southeastern China.The results show that:The first velocity is 6.0km/s,it is close to Press's results;the π_g wave has shown normal dispersion,and a few are no-normal dispersion;its paramount period is 0.6-0.8 second.Using the composite amplitude of horizontal component of the π_g wave,we have obtained the radiation pattern of the π_g wave,it is basically close to radiation pattern in weak heterogeneous medium.There is the D value of time of incidence (Phase Shift) between horizontal time and vertical time of the π_g wave number.